Fig. 3: Surface-mapped ventilation and re-exposure rates and mean transit times.
From: Diffusion controls the ventilation of a Pacific Shadow Zone above abyssal overturning
The normalized ventilation flux \({\widehat{{{\Phi }}}}^{\downarrow }\) from the surface to the Pacific Shadow Zone (PSZ) (a) and from the surface to the Pacific Abyssal Zone (PAZ) (c). The normalized re-exposure flux \({\widehat{{{\Phi }}}}^{\uparrow }\) from the PSZ to the surface (b) and from the PAZ to the surface (d). Because the dynamic range of these fluxes spans several orders of magnitude, plotted are the base-10 logarithm of \({\widehat{{{\Phi }}}}^{\downarrow }/{{{\Phi }}}_{0}\) and \({\widehat{{{\Phi }}}}^{\uparrow }/{{{\Phi }}}_{0}\), where Φ0 = 1 m−2. The total surface-integrated fluxes in units of Sv = 106 m3 s−1 are indicated in the plot titles. The difference between the PAZ and PSZ normalized ventilation fluxes (e) and between the PAZ and PSZ normalized re-exposure fluxes (f). The side panels of (a–h) show the global zonal integrals (not normalized) per degree of latitude. (Unperturbed base state in red, sensitivity perturbations in grey.) The mean transit times Γ↓ from a given surface point to an interior point, and the mean transit times Γ↑ from an interior point to a given surface point, averaged over the PSZ (g, h) and over the PAZ (i, j). Γ↓ and Γ↑ are plotted only for normalized fluxes (unity surface integral) larger than 0.5 × 10−16 m−2 because of numerical issues in calculating the mean transit times for smaller flow rates.
